Long-term survival and immunological parameters in metastatic melanoma patients who responded to ipilimumab 10 mg/kg within an expanded access programme

Background

Ipilimumab can result in durable clinical responses among patients with advanced melanoma. However, no predictive marker of clinical activity has yet been identified. We provide preliminary data describing the correlation between immunological parameters and response/survival among patients with advanced melanoma who received ipilimumab 10 mg/kg in an expanded access programme.

Methods

Patients received ipilimumab 10 mg/kg every 3 weeks (Q3W) for four doses (induction) and Q12W from week 24 (W24) as maintenance therapy. Tumor assessments were conducted Q12W. Expression of inducible T cell costimulator (ICOS) on CD4⁺ and CD8⁺ T cells was assessed at baseline, W7, W12 and W24, and the ratio between absolute neutrophils (N) and lymphocytes (L) determined at baseline, W4, W7 and W10.

Results

Median overall survival among 27 patients was 9.6 months (95 % CI 3.2–16.1), with 3- and 4-year survival rates of 20.4 %. Five patients survived >4 years. Patients with an increase in the number of circulating ICOS⁺ T cells at W7 were more likely to experience disease control and have improved survival. An N/L ratio below the median at W7 and W10 was also associated with better survival compared with an N/L ratio above the median.

Conclusions

Ipilimumab can induce long-term survival benefits in heavily pretreated patients with metastatic melanoma. Changes in the number of circulating ICOS⁺ T cells or N/L ratio during ipilimumab treatment may represent early markers of response. However, given the limited sample size, further investigation is required.     

Notch-signalling is required for head regeneration and tentacle patterning in Hydra

Local self-activation and long ranging inhibition provide a mechanism for setting up organising regions as signalling centres for the development of structures in the surrounding tissue. The adult hydra hypostome functions as head organiser. After hydra head removal it is newly formed and complete heads can be regenerated. The molecular components of this organising region involve Wnt-signalling and β-catenin. However, it is not known how correct patterning of hypostome and tentacles are achieved in the hydra head and whether other signals in addition to HyWnt3 are needed for re-establishing the new organiser after head removal. Here we show that Notch-signalling is required for re-establishing the organiser during regeneration and that this is due to its role in restricting tentacle activation. Blocking Notch-signalling leads to the formation of irregular head structures characterised by excess tentacle tissue and aberrant expression of genes that mark the tentacle boundaries. This indicates a role for Notch-signalling in defining the tentacle pattern in the hydra head. Moreover, lateral inhibition by HvNotch and its target HyHes are required for head regeneration and without this the formation of the β-catenin/Wnt dependent head organiser is impaired. Work on prebilaterian model organisms has shown that the Wnt-pathway is important for setting up signalling centres for axial patterning in early multicellular animals. Our data suggest that the integration of Wnt-signalling with Notch-Delta activity was also involved in the evolution of defined body plans in animals.     

Inhibition of VEGF-C Modulates Distal Lymphatic Remodeling and Secondary Metastasis

Tumor-associated lymphatics are postulated to provide a transit route for disseminating metastatic cells. This notion is supported by preclinical findings that inhibition of pro-lymphangiogenic signaling during tumor development reduces cell spread to sentinel lymph nodes (SLNs). However, it is unclear how lymphatics downstream of SLNs contribute to metastatic spread into distal organs, or if modulating distal lymph transport impacts disease progression. Utilizing murine models of metastasis, longitudinal in vivo imaging of lymph transport, and function blocking antibodies against two VEGF family members, we provide evidence that distal lymphatics undergo disease course-dependent up-regulation of lymph transport coincidental with structural remodeling. Inhibition of VEGF-C activity with antibodies against VEGF-C or NRP2 prevented these disease-associated changes. Furthermore, utilizing a novel model of adjuvant treatment, we demonstrate that antagonism of VEGF-C or NRP2 decreases post SLN metastasis. These data support a potential therapeutic strategy for inhibiting distant metastatic dissemination via targeting tumor-associated lymphatic remodeling.     

Functional ESCRT machinery is required for constitutive recycling of claudin-1 and maintenance of polarity in vertebrate epithelial cells

Genetic screens in Drosophila have identified regulators of endocytic trafficking as neoplastic tumor suppressor genes. For example, Drosophila endosomal sorting complex required for transport (ESCRT) mutants lose epithelial polarity and show increased cell proliferation, suggesting that ESCRT proteins could function as tumor suppressors. In this study, we show for the for the first time to our knowledge that ESCRT proteins are required to maintain polarity in mammalian epithelial cells. Inhibition of ESCRT function caused the tight junction protein claudin-1 to accumulate in intracellular vesicles. In contrast E-cadherin and occludin localization was unaffected. We investigated the cause of this accumulation and show that claudin-1 is constitutively recycled in kidney, colon, and lung epithelial cells, identifying claudin-1 recycling as a newly described feature of diverse epithelial cell types. This recycling requires ESCRT function, explaining the accumulation of intracellular claudin-1 when ESCRT function is inhibited. We further demonstrate that small interfering RNA knockdown of the ESCRT protein Tsg101 causes epithelial monolayers to lose their polarized organization and interferes with the establishment of a normal epithelial permeability barrier. ESCRT knockdown also reduces the formation of correctly polarized three-dimensional cysts. Thus, in mammalian epithelial cells, ESCRT function is required for claudin-1 trafficking and for epithelial cell polarity, supporting the hypothesis that ESCRT proteins function as tumor suppressors.     

Ipilimumab experience in heavily pretreated patients with melanoma in an expanded access program at the University Hospital of Siena (Italy)

Aim of study

To evaluate the feasibility of ipilimumab treatment for metastatic melanoma outside the boundaries of clinical trials, in a setting similar to that of daily practice.

Methods

Ipilimumab was available upon physician request in the Expanded Access Programme for patients with life-threatening, unresectable stage III/IV melanoma who failed or did not tolerate previous treatments and for whom no therapeutic option was available. Induction treatment with ipilimumab 10?mg/kg was administered intravenously every 3?weeks, for a total of 4 doses, with maintenance doses every 12?weeks based on physicians?? discretion and clinical judgment. Tumors were assessed at baseline, Week 12, and every 12?weeks thereafter per mWHO response criteria, and clinical response was scored as complete response (CR), partial response (PR), stable disease (SD), or progressive disease. Durable disease control (DC) was defined as SD at least 24?weeks from the first dose, CR, or PR.

Results

Disease control rate at 24 and 60?weeks was 29.6% and 15%, respectively. Median overall survival at a median follow-up of 8.5?months was 9?months. The 1- and 2-year survival rates were 34.8% and 23.5%, respectively. Changes in lymphocyte count slope and absolute number during ipilimumab treatment appear to correlate with clinical response and survival, respectively. Adverse events were predominantly immune related, manageable, and generally reversible. One patient died from pancytopenia, considered possibly treatment related.

Conclusion

Ipilimumab was a feasible treatment for malignant melanoma in heavily pretreated, progressing patients. A sizeable proportion of patients experienced durable DC, including benefits to long-term survival.     

In vitro analysis of the melanoma/endothelium interaction increasing the release of soluble intercellular adhesion molecule 1 by endothelial cells

Melanoma cells constitutively release intercellular adhesion molecule 1 (ICAM-1) as soluble ICAM-1 (sICAM-1), and its levels are elevated in melanoma patients and correlate with disease progression. However, this correlation is not absolute, suggesting that specific characteristics of neoplastic cells and/or ICAM-1-positive non-neoplastic cells may influence the amounts of circulating sICAM-1. In this study, we found a weak correlation (r = 0.55; r ² = 0.3) between sICAM-1 release by 40 metastatic melanomas (36 primary cultures and 4 cell lines), and ICAM-1 expression on neoplastic cells. In addition, melanoma-secreted interleukin-1α (IL-1α) (1/40) but not vascular endothelial growth factor (VEGF) (29/40), significantly (P < 0.05) up-regulated the shedding of sICAM-1 by human umbilical vein endothelial cells (HUVEC). This was completely abolished by IL-1α/β neutralizing antibodies both at the protein and mRNA level. Altogether, our results suggest that (i) the extent of sICAM-1 release is distinctive for individual melanomas and can be independent of ICAM-1 expression; (ii) tumor endothelia may sustain levels of sICAM-1 in selected melanomas; (iii) melanoma-released VEGF does not affect ICAM-1 expression and sICAM-1 release by HUVEC. Melanoma-derived sICAM-1 inhibits cell-mediated cytotoxicity of melanoma cells; therefore, constitutive levels of sICAM-1 release and IL-1α secretion by individual melanomas can differentially influence tumor progression and the clinical effectiveness of cytotoxic-cell-based vaccines. Received: 15 October 1998 / Accepted: 17 February 1999     

Information Transfer in Gonadotropin-releasing Hormone (GnRH) Signaling: EXTRACELLULAR SIGNAL-REGULATED KINASE (ERK)-MEDIATED FEEDBACK LOOPS CONTROL HORMONE SENSING*

Cell signaling pathways are noisy communication channels, and statistical measures derived from information theory can be used to quantify the information they transfer. Here we use single cell signaling measures to calculate mutual information as a measure of information transfer via gonadotropin-releasing hormone (GnRH) receptors (GnRHR) to extracellular signal-regulated kinase (ERK) or nuclear factor of activated T-cells (NFAT). This revealed mutual information values <1 bit, implying that individual GnRH-responsive cells cannot unambiguously differentiate even two equally probable input concentrations. Addressing possible mechanisms for mitigation of information loss, we focused on the ERK pathway and developed a stochastic activation model incorporating negative feedback and constitutive activity. Model simulations revealed interplay between fast (min) and slow (min-h) negative feedback loops with maximal information transfer at intermediate feedback levels. Consistent with this, experiments revealed that reducing negative feedback (by expressing catalytically inactive ERK2) and increasing negative feedback (by Egr1-driven expression of dual-specificity phosphatase 5 (DUSP5)) both reduced information transfer from GnRHR to ERK. It was also reduced by blocking protein synthesis (to prevent GnRH from increasing DUSP expression) but did not differ for different GnRHRs that do or do not undergo rapid homologous desensitization. Thus, the first statistical measures of information transfer via these receptors reveals that individual cells are unreliable sensors of GnRH concentration and that this reliability is maximal at intermediate levels of ERK-mediated negative feedback but is not influenced by receptor desensitization.